During the production of many products it is often desirable to heat the product. In some cases the heat may be applied in order to disinfect the product, pre-cook the product, and/or remove water content from the product. While there are many methods for applying heat to a product (boiling, convection, conduction, steam, etc.), for several reasons it may often be desirable to use microwaves as the method for heating the product. As is known in the art, applying microwave energy causes polarized molecules to quickly move in order to align with the oscillating microwave. This quick movement causes the molecules to heat up, also known as dielectric heating.
While others have attempted to apply microwave energy to products in a uniform and repeatable manner, attempts thus far have fallen short. Previous systems and methods have been unable to match the microwave energy with the product so that there is uniform heating. Previous techniques have produced uneven heating due to the non-uniform distribution of microwave energy inside the oven. Some oven designs produce ‘hot’ spots and ‘cold’ spots which receive microwave energy in different amounts. Typically, the composition and geometry of the product creates problems for previous designs. Most notably, the thickness or depth of the product can produce situations where the outer layer has been heated while the interior remains at a lower temperature. Previous designs have attempted to apply more microwave energy in order to reach the interior of the product. However, because microwaves are by-design non-uniform, the problem is only amplified when more microwave energy is applied to the product.
Previous designs have used antennas or other ‘stirring devices’ which were designed to spread the microwave energy waves throughout the oven, mostly in a random scattering-type manner. It has been found that these techniques are not very controllable or uniform in their application of microwave energy to a given product.